Estimation of Sludge Centrifuge Performance

The laboratory bottle centrifuge is used to evaluate the possibility of dewatering any particular sludge by centrifugation. Two variables, centrifugal force and residence time, are assumed to be of primary importance, and other machine variables are secondary. Centrifugal force and residence time can be duplicated with the laboratory machine. A model which describes both the settling and scrolling processes is used for predicting centrifuge performance. Settleability is measured by spinning 10 ml samples in the bottle centrifuge and measuring the suspended solids in the centrate. Sludge solids consistency, which indicates the ease of scrolling, is measured by a penetration test, in which a light, fluffy sludge, which is difficult to scroll in a prototype, also gives poor penetration values. The percent recovery is then calculated by an empirical model. The difference between the estimated recovery and the prototype performance can be expected to be within plus or minus 10%.